Working with High-Bit Files

Many higher-end digital cameras are capable of capturing a 12-bit image. This translates to 4096 tonal levels per color channel instead of the 256 levels in an 8-bit file. That represents quite a bit more tonal information. In Photoshop a file with more than 8-bits per pixel is classified as a 16-bit image. Since digital color correction involves selectively discarding information in order to get the existing data looking the way you want, more individual tonal levels means more room, or a bigger stage, on which to perform your corrections. When you start out with many more tonal levels in your file, it's not as critical if some levels are lost in the quest to make the image look better (Figure 11.94). The ability to apply broad corrections and not sacrifice significant amounts of the tonal range in the process represents a huge advantage for preserving the highest possible quality in your images. The advantages of working with high-bit data mean much more control and quality throughout the color correction process, especially for images that need a lot of work.

Figure 11.94. The same Levels tonal correction was directly applied (no adjustment layers) to two versions of this image, one 8-bit and one 16-bit. After running Levels on the images, their histograms can tell us a lot. In the 8-bit file (B) significant tonal erosion has occurred, but the histogram for the 16-bit file (C) is not damaged.